﻿using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;

namespace FreedomX2.Core.Encrypt
{
    public class DEncrypt
    {

        #region 加密和解密功能
        /// 加密
        /// </summary>
        /// <param name="str"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        public static string Encode(string str, string key)
        {
            StringBuilder builder = new StringBuilder();
            try
            {
                DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
                provider.Key = Encoding.ASCII.GetBytes(key.Substring(0, 8));
                provider.IV = Encoding.ASCII.GetBytes(key.Substring(0, 8));
                byte[] bytes = Encoding.GetEncoding("GB2312").GetBytes(str);
                MemoryStream stream = new MemoryStream();
                CryptoStream stream2 = new CryptoStream(stream, provider.CreateEncryptor(), CryptoStreamMode.Write);
                stream2.Write(bytes, 0, bytes.Length);
                stream2.FlushFinalBlock();

                foreach (byte num in stream.ToArray())
                {
                    builder.AppendFormat("{0:X2}", num);
                }
                stream.Close();
            }
            catch { }
            return builder.ToString();
        }
        /// <summary>
        /// Des 解密 GB2312 
        /// </summary>
        /// <param name="str">Desc string</param>
        /// <param name="key">Key ,必须为8位 </param>
        /// <returns></returns>
        public static string Decode(string str, string key)
        {
            try
            {
                DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
                provider.Key = Encoding.ASCII.GetBytes(key.Substring(0, 8));
                provider.IV = Encoding.ASCII.GetBytes(key.Substring(0, 8));
                byte[] buffer = new byte[str.Length / 2];
                for (int i = 0; i < (str.Length / 2); i++)
                {
                    int num2 = Convert.ToInt32(str.Substring(i * 2, 2), 0x10);
                    buffer[i] = (byte)num2;
                }
                MemoryStream stream = new MemoryStream();
                CryptoStream stream2 = new CryptoStream(stream, provider.CreateDecryptor(), CryptoStreamMode.Write);
                stream2.Write(buffer, 0, buffer.Length);
                stream2.FlushFinalBlock();
                stream.Close();
                return Encoding.GetEncoding("GB2312").GetString(stream.ToArray());
            }
            catch { }
            return "";
        }
        #endregion

        #region 通用java加密解密
        public static string DESEncode(string pToEncrypt, string sKey)
        {
            //pToEncrypt = HttpContext.Current.Server.UrlEncode(pToEncrypt);
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.GetEncoding("UTF-8").GetBytes(pToEncrypt);

            //建立加密对象的密钥和偏移量    
            //原文使用ASCIIEncoding.ASCII方法的GetBytes方法    
            //使得输入密码必须输入英文文本    
            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);

            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                ret.AppendFormat("{0:X2}", b);
            }
            ret.ToString();
            return ret.ToString();
        }
        #endregion

        #region DESDeCode DES解密
        public static string DESDecode(string pToDecrypt, string sKey)
        {
            //    HttpContext.Current.Response.Write(pToDecrypt + "<br>" + sKey);   
            //    HttpContext.Current.Response.End();   
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
            for (int x = 0; x < pToDecrypt.Length / 2; x++)
            {
                int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
                inputByteArray[x] = (byte)i;
            }

            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            StringBuilder ret = new StringBuilder();

            return System.Text.Encoding.Default.GetString(ms.ToArray());
        }
        #endregion

        /// <summary>
        /// MD5 Web加密
        /// </summary>
        /// <param name="strContext"></param>
        /// <returns></returns>
        public static string GetMD5ByWeb(string strContext)
        {
            return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(strContext, "MD5");
        }

        /// <summary>
        /// MD5 Bytes加密
        /// </summary>
        /// <param name="strContext"></param>
        /// <returns></returns>
        public static string GetMD5ByBytes(string strContext)
        {
            byte[] result = Encoding.Default.GetBytes(strContext);
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] output = md5.ComputeHash(result);
            return BitConverter.ToString(output).Replace("-", "");
        }

        /// <summary>
        /// MD5 Convert32to16
        /// </summary>
        /// <param name="strContext"></param>
        /// <returns></returns>
        public static string MD5Convert32to16(string strContext)
        {
            return strContext.ToLower().Substring(8, 16);
        }
    }
}
